Study on warpage evolution for six-side molded WLCSP based on finite element analysis

Wafer warpage has been an important problem to affect the manufacturability and reliability in Wafer Level Chip Scale package (WLCSP). In this paper, wafer warpage evolution is studied for a six-side molded WLCSP using finite element model. A method to mimic the actual fabricating process is presented based on the "Element birth & death" and "Restart" technology. Key process such as topside molding, backside grinding and backside molding is taken into account and the results match with the experiment well. The effect of the parameters and structural parameters on wafer warpage characteristics is analyzed.